Soy-based polyols are of interest because they are produced from renewable and domestic feed stocks rather than non-renewable petroleum-based feed stocks. Another advantage of soy-based polyols is the low cost of the feed stocks.
A variety of processes have been employed to produce polyols. Blown vegetable oils are an example of a soy-based polyol. U.S. Pat. Nos. 6,476,244 and 6,759,542 describe methods of synthesizing blown vegetable oils, which include use of air blown through the vegetable oils at elevated temperatures to promote partial oxidation. U.S. Pat. No. 6,686,435 describes a method of making natural oil-based polyols consisting of reacting the epoxy moiety of an epoxidized natural oil with a hydroxyl moiety of an alcohol in the presence of 10% to 30% water. U.S. Pat. No. 6,258,869 is on a process for production of polyols by reacting an agricultural feed stock with a multi-functional alcohol in the presence of a tin catalyst. U.S. Pat. No. 5,482,980 describes a method of preparing a flexible foam by using an epoxidized soybean oil at 7 to 25 parts by weight per hundred parts polyol.
A need, therefore, exists in the art for a process to convert vegetable oils to polyols of higher molecular weight that is more efficient and economical than those described in the prior art.